US1779823A

US1779823A - Automatic cylindrical grinding machine

Info

Publication number: US1779823A
Application number: US59158A
Authority: US
Inventors: Charles H Norton
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1925-09-28
Filing date: 1925-09-28
Publication date: 1930-10-28
Anticipated expiration: 1947-10-28

Description

Oct. 28, 1930. c. H. NORTON AUTOMATIC CYLINDRICAL GRINDING MACHINE Filed Sept.

2 1925 5 Sheets-Sheet 1 INVENTOR Charles H. lYorTan Q NESS S W um ATTORNEY Oct. 28, 1930. -c. H. NORTON AUTOMATIC CYLINDRICAL GRINDING MACHINE 'Fiied Sept. 28 1925 5 Sheets-Sheet 2 mvzmoa Cha r/es H A a/Ton A RNEY Oct. 28, 1930.

C. H. NORTON AUTOMATIC CYLINDRICAL GRINDING MACHINE Filed Sept. 28 1925 5 Sheets-She et s INVENTOR Charles H. IYorTon Oct. 28, 1930. c. H. NORTON AUTOMATIC CYLINDRIOAL GRINDING MACHINE Filed Sept. 28, 1925 5 Sheets-Sheet 4 2o as 16 21 m WITN E8855 W mu;

INVENTOR Char/es H. AWE/1 mwrola m Oct. 28, 1930. c. H. NORTON AUTOMATIC CYLINDRICAL GRINDING MACHINE Filed Sept. 28 9 5 5 Sheets-Sheet 5 F90 INVENTOR Char/es H. l orfon WITNESSES Mum ATTO EY Patented Oct. 28, 1930 UNITED STATES PATIENT OFFICE CHARLES H. NORTON, OF PLAIN VILLE, CONNECTICUT, ASSIGNOB TO NORTON COMPANY, OF WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS AUTOMATIC GYLINDRICAL GRINDING MACHINE Application filed September 28, 1925. Serial Ru. 58,158.

My invention relates to a grinding machine and more particularly to an automatic machine for grinding cylindrical objects.

The ordinary plain cylindrical grinding machine is too slow for rapid production of small cylindrical objects, since a large number of 0 erations are required of the operator while the machine remains idle. In using such a machine, when a piece of work has been ground to size, it is necessary for the operator to stop the'motion of the machine, turn the feed mechanism to remove the grinding wheel from the work, move the footstock center, and manually remove the piece of work from the centers. He then takes the next rough piece of work to be ground, Wl'llCll has previously been dogged, and inserts it in axial alignment between the centers. This being done, he brings the footstock center into position to support the work and starts the machine in motion, after which he must feed the wheel into the work and occasionally stop to caliper the work and make sure of getting it to size. It will be readily seen that considerable time is lost, by having to perform all these operations, and it is seldom that work is of such a size and character that an operator can run more than one of these machines at a time.

It is an object of my invention to overcome such diificulties and to increase production when a large number of duplicate pieces are to be ground by providing a machine which may be fully or partially automatic m operation and thereby require but little attention on the part of the operator.

A desirable type of automatic grindin machine is one which is so arranged that the work may be placed in a hopper by the operator and from there fed mto axial alignment with automatically 0 rated rippin members which support an rotate t e wor during the grinding operation. The ieces of work should be ground successive y by feeding the grinding wheel with extreme precision through a. predetermined distance and then withdrawing it for removal of the finished work and re lacelnent by a fresh piece. To feed the wheel mechanism which goes through a cycle of into the work requires a operations and which is capable of fine adjustments and will produce uniform and duplicate results repeatedly. The operator should be required merely to fill the magazine with rough pieces of work to be sized, and from time to time make sli ht adjustments to take care of any wear of the grinding wheel. vIt is accordingly a further object of my invention to provide a wheel feeding mechanism which will operate automatically and repeatedly to feed the wheel accurately into the work to a predetermined position, so as to grind the work to an exact size, and then to remove the wheel and permit replacement of the work. and particularly to utilize the standard nut and screw cross feed mechanism for this purpose y providing a cam mechanism capable of turning the cross feed screw through the desired cyclic movement.

A further object is to provide a manual control for the cross feed which is so arranged that the wheel may be repeatedly and eyelically fed through mined distance so as to grind different sizes of work with a minimum of lost motion.

A further object is to combine with i the feeding mechanism a stopping device which may be adjusted to insure stopping the grindmg when the work has reached a predetermined size.

Another object is to provide such an automatic cross feed mechanism with a manually adjustable precision device which makes it feasible to set the grinding wheel in any desired position relative to the work, as well g as to take up for wheel wear and to feed the wheel into the work manually'or automatically as desired.

It is a still further object of my invention to provide an automatic grinding machine of this type, in which the grinding wheel is fed straight into the work by power operation of a cross feed screw, with a mechanism which reciprocates the grinding wheel axially and thereby eliminates grain markings showing on the work.

, A further object is to provide a fully automatic grinding machine in which the work a variable but predeter-.

piecesare successively gripped by and released from work supporting members, and to provide mechanism coordinating such an operation with the wheel feeding movement, to that they will be carried on in a proper timed relation.

With these and other objects in view as will be apparent to one skilled in the art, my invention resides in the combination of parts set forth in the accompanying description and covered by the claims appended hereto.

I have illustrated in the drawings a machine including all of the various features of my invention so arranged as to operate automatically, but certain of these features may be incorporated. as desired, in a semi automatic machine intended to be manually controlled for grinding a single piece of work at a time, and it is to be understood that such suhcombinations fall within the scope of my invention.

Referring to the drawings in which like reference numerals indicate like parts: 1

Figure 1 is a front elevation of my automatic grinding machine having portions broken away to more clearly show the inside mechanism;

Fig. 2 is an end elevation of my machine, with portions of the base similarly broken away;

F1 3 is an enlarged fragmentary view showing the spindle operating mechanism;

Fig. 4 is an enlarged end elevation of the parts shown in Fig. 3;

Fig. 5 is an enlarged fragmentary end view showing the magazine turret mechanism for feeding the work to its grinding position;

Fig. 6 is an enlarged rear view of the magazine turret mechanism;

Fig. 7- is an enlarged fragmentary sectional view taken approximately on the line 77 of Fig. 5;

Fig. 8 is an enlarged fragmentary view taken approximately on the line 8-8 of Fig. 2 showing the cam operated feed mechanism and the indexing mechanism for, the work turret;

Fig. -9 is an enlarged fragmentary view taken approximately on the line 99 of Fig. 2 showing a portion of the feed mechanism and stop;

Fig. 10 is an enlar lever shown in Fig. 8 pawl;

Fig. 11 is an enlarged sectional detail view taken approximately on the line 11-11 of Fig 10;

ig. 12 is a fragmentary section on the line 12-12 of Fig. 2;

Fig. 13 is an enlar ed fragmentary detail view showing the afjustable mounting for the work spindle drive shaft to tension the driving chains;

Fig. 14 is an enlarged sectional view showing a modified type of work holder;

ed detail view of the or tripping the ratchet -weight of the work Fig. 15 is an enlarged fragmentary end view partly in section of a modified form of turret operating mechanism;

Fig. 16 is an enlarged fragmentar front elevation of the mechanism shown in ig. 15;

Fig. 17 is a fragmentary end elevation partly of work presenting mechanism; and

Fig. 18 is a fragmentary rear elevation of the mechanism shown in Fig. 17

In my preferred construction, I have illustrated an automatic grinding machine in which the work is placed in a hopper and is then fed automatically into axial alignment with a pair of rotatable work supporting spindles, which are arranged to move toward the ends of the work to grip it adja cent its periphery for rotating it by frictional contact. In order to feed the grinding wheel and the work relatively towards each other, one of these, and preferably the wheel, is mounted on a slide, and this slide is moved precisely by means of a cross feed screw mechanism. This is operated by a power drive which is preferably controlled by a cam so as to move in timed relation with the work supporting spindle mechanism. I prefer to feed the slide forward by an adjustable weight and to move it back positively by the cam mechanism, and I so arrange the parts that the grinding wheel is fed rapidly at the start and then with a slow and uniform feeding motion until the work has been reduced to its approximate size, at which point the feed mechanism engages a stop which prevents further feeding movement of the grinding wheel and permits the wheel to grind out or finish grind the work. The cam is preferably so shaped that when the work has been finished, it moves the slide rapidly in the opposite direction to remove broken away showing a modified form the grinding wheel from the work. Likewise. the work gripping mechnism is preferably operated in one direction to grip the work by an adjustable weight and in the opposite direction by a power driven cam. The work may be fed to the work supports by hand or automatically, as by means of a turret wheel which is moved in timed relation with the spindles to present the work thereto and then remain stationary during the grinding operation. The turret may be moved positively by a power drive or the may be utilized to rotate it, and a cam operated control device insures that the wheel remains immovable except when release of the finished work and feeding of a new piece is required. I also provide a wheel spindle reciprocating mechanism to oscillate or reciprocate the grinding wheel spindle axially through a short distance so that the wheel will wear evenly and prevent the formation of grain markings on the work being ground.

Referring to the drawings,I have there of the machine.

shown the machine base 10 as made in two parts, one the front base 11 and the other the rear base 12 (Figs. 1 and 2). The rear base 12 carries the usual grinding wheel slide 13 which is adapted to slide transversely on the usual V-way 14 and flat wa 15 mating with correspondin ways on the ase. The grind ing wheel sli e carries a grinding wheel spindle 18 which is mounted in suitable bearings in the wheel slide and carries on one end a grinding wheel 19, as clearly illustrated and described in my prior Patent No. 1,443,924.

A pair of rotatable axially slidable work supporting spindles 20 and 21 (Figs. 2 and 3) are journaled in the front base of the machine in two pairs of

bearings

22 and 23 respectively, which may be of suitable construction. These spindles are preferably so arranged that they may be driven in synchronism' with each other so as to produce a proper rotation of the work.

Powerdfim'ng mechanism As shown in Fig. 2, the rear base is provided with a main drive shaft 30, driven by any suitable source of power, which carries a pulley 32 to transmit power to the wheel spindle 18 by means of a belt 33 passing over a Dulley 34 on the wheel spindle 18 and an idler belt tensioning pulley 35. Power may be transmitted to the front base of the machine from the main drive shaft by a sprocket thereon and a link drive chain 41 to the sprocket 42 on the shaft 43. The sprocket 42 is rotatably mounted on the shaft 43 and is so constructed that it may be connected or disconnected from the shaft by means of a suitably constructed clutch 44 which is operated by the usual oked member 45 pivoted to the base at 46 and the manually operable lever 47. The shaft 43 is connected by a coupling 49 to the shaft 50 which carries a spur gear 51 meshing with a s ur gear 52 on the short shaft 53. The sha 53 carries on its other end a spur gear 54 meshing with a s ur gear 55 on the cross shaft 56 which exten This shaft 56 carries the

sprockets

60 and 61 respectively which drive the

link chains

64 and 65. These in turn drive the sprockets 66 and 67 on the

work supporting spindles

20 and 21 respectively. The chains 64and 65 are of suflicient length and have enough flexibility so that the sprockets 66 and 67 may be fixed to the axially

slidable work spindles

20 and 21.

The

gears

54 and 55 are preferably change gears and are so constructed that they may be readily removed and replaced by other combinations to vary the work rotating speed. These gears 54 and 55, as illustrated,"are arranged to give a slow speed rotation of the work support spindles. By removing them and placing the larger gear 55 on the shaft 53 and the smaller gear 54 on the shaft 56 the s the length speed of rotation of the work supporting spindles may be increased.

H To permit tensioning the

link drive chains

64 and 65, I preferably mount the shaft 56 in the two swinging brackets 7 0 and 71 (Fig. 13) which are arranged to swing about the axis of the shaft 53 as a pivot, so that for any position of the shaft 56, the

gears

54 and 55 are always in mesh. The brackets 7 O and 71 are each provided with an elongated slot 73 and a set screw 74 which passes through the elongated slot and is screw threaded into a portion of the base of the machine. It will thus be readily seen that the brackets and 71 may be separately adjustable and locked in a desired position, so that either of the

chains

64 and 65 may be tensioned without disturbing the driving tension of the other.

Gross feed mechanism One of the main features of my invention has to do with obtaining a precise and duplicatable feeding movement of the wheel into the work. To this end, I mount one of these, and preferably the grinding wheel, on a cross slide and connect a feed screw thereto. This feed screw is rotated automatically by a power mechanism, and the rate of rotation and direction of movement is accurately controlled by a further automatic device, which is preferably a cam, so that the wheel is fed forward a predetermined amount and then withdrawn. Successive pieces of work may be brought to the same exact size by utilizing an adjustable stop so arranged that the feed screw may not be turned beyond a certain point, irrespective of the operation of the cam and power drive therefor. The power is best applied b means of an adjustable weight arrange to feed the wheel into the work as permitted by the cam, and the latter serves to withdraw the wheel and lift the Weight for the next infeed operation.

A further im ortant feature lies in a construction which permits one to var the length of the feeding stroke without changing the cam. This is simply accomplished by connecting the cam with the screw by means of a chain passing over a sprocket on the screw shaft and adjustably connected to an involute sha ed lever which is oscillated b the cam. Tl fe point of connection of the c ain with the lever may be adjusted to change the effective length of the lever arm, and this-serves merely to wrap the chain about the sprocket without turning the screw.

While the slide may be moved by various types of cross feed mechanism, I prefer to employ one which is patterned generally after that shown in my prior Patents No. and 'No. 1,443,924. This mechanism comprises a half-nut secured to the under side of the wheel slide 13 which is screw threaded to engage a plurality of corresponding threads on a feed screw 81. The feed screw is journalled in the rear base of the I and rate of travel of the wheelinto machine and carries on its front end a fgear 83 meshing with a pinion 84 on the sha t 85 journalled in the front base of the machine. The shaft 85 carries a gear 86 meshing with a gear 87 on the shaft 88, on which is mounted the gear wheel 89 arranged to turn the feed screw. The hand feed lever 92 is rotatably mounted on a projection of the shaft 88 and carries a micrometer adjusting mechanism 93, such as is clearly described in my prior Patent No. 762,838 and the patent to Wilcox No. 1,261,083. This mechanism permits adjusting the feed arm 94 relative to the gear wheel 89, and comprises a pinion 95 meshing with the gear 89 and a crank arm 96 adjustably clamped to the extension 97 of the pinion shaft 95. By pulling the plunger 98 from the opening 99 in the index plate 100, the crank arm 96 may be turned the desired amount to adjust the arm 94 relative to the gear wheel 89. When in adjusted position the plunger 98 may be reinserted in the nearest opening 99 in the index plate 100. This makes it possible to position the grinding wheel as desired relative to. the work, to ad- 'ust for wheel wear, or even to feed the wheel y hand when considered necessary.

Cam controlled power drive for feed screw The feed screw is rotated by a cam mechanism, including a cam and a follower operatively connected to the feed screw, which is so constructed and arranged that the distance and awe from the work are predetermined in accor ance with the contour shape of the cam. The embodiment illustrated comprises an adjustable weight connected to the screw by a chain and sprocket, and the movement of the weight is controlled by a power driven cam. To this end, I may mount a cam 110 on the shaft 111 which is journalled in the front base of the machine. To positively rotate the cam 110, a worm 112 is mounted on the shaft 50 (Fig. 1) in mesh with a worm gear 113 mounted on the shaft 114. The other end of the shaft 114 carries a gear 115 (Figs. 2, 3 and 4) which in turn meshes with an intermediate gear 116, arranged to drive a gear 117 on the cam shaft 111 to rotate the cam 119. i

To permit varying the speed of rotation of the cam and consequengly the speed at which the grinding wheel is f inwardly, I employ a suitable change gear mechanism. This may be simply accomplished by mounting the gear 116 on a swin ing arm 120, which swings about the axis of t e cam shaft 111 as a ivot. The small gear 115 is preferably a c ange gear which 1s so constructed that it may readily be sli ped into place or taken oil? and changed or a let er or smaller gear. The arm 120 is prefers. ly a bell crank, having a projecting arm 121 by which the gear 116 may be swung into mesh with the change gear 115. The gear 116 is locked in its adjusted position by a clamping screw 123, which slides within the arcuate slot 124 in the member 125. This member 125 is fixed inside the machine by the threaded studs 126 (Fig. 2).

To transmit the motion of the cam 110 so as to control the movement of the feed mechanism, I mount a lever 130 (Figs. 1, 8 and 12) on a pivot 131 on the base of the machine. The short arm 132 of the lever 130 carries a follower roller 133 which is adapted to enga e the operative surface of the cam 110. A re ially extending arm 135 havin a projecting hub 136 is journalled on the s aft 88 and is provided at its outer end with a locking screw 137 adapted to lock the arm 135 to a projection of the arm 94. The member 135 carries a sprocket 138 on its projecting hub 136. To transmit the cam motion from the lever 130 to the feed mechanism, I employ a link chain 140 which passes over the sprocket 138 and has one end adjustably connected to the arm 145 by a slidable clamping member 142. The lower end of the chain 140 is connected to a weight 143 which is slidably mounted in the housing or bracket 144 secured to the base of the machine. The weight 143 is of sufficient size to turn the feed screw to feed the grinding wheel into the work and to keep the cam follower roller 133 always in contact with the surface of the cam .110.

The feed cam 110 is preferably of such a shape that it will cause the grinding wheel to be fed rapidly toward the work for a short period of time until it is about to contact with the work, and thereafter be moved at a slow and uniform rate until the'work has been reduced to its approximate size. During the final stage of grinding the feed mechanism is held immovable by a stop mechanism for a short period of time to rmit the grinding wheel to finish the grin ing operation. a

From this disclosure, it will be readily seen that the weight 143 turns the feed screw as limited by the shape and motion of the cam 110 to produce the feeding action of the grinding wheel toward the work. The return motion of the grinding wheel caused by the abrupt rise on the cam positively turns the feed screw in the opposite direction against the action of the weight 143, and moves the grinding wheel rearwardly to its initial position.

F eed stop device 135. The sto screw 146 is preferably so'adjusted that t e arm 135 contacts with the screw 146 before the cam follower roller 133 reaches the end of the infeed portion of the cam. With this adjustment, it will be readily seen that the stop screw 146 positively limits the feedin movement of the grinding wheel at a pre etermined point, since the cam mechanism acts, not directly upon a massive wheel slide, but upon the feed screw, and it is possible to turn the latter with a fine degree of precision and therefore feed the grinding wheel exactly to a predetermined position and reduce pieces of work to a desired size successively and uniformly. Moreover, when the stop becomes effective, the feed control cam may continue to rotate butfithe stop holds the cam follower out of contact with the cam until it is time to move the wheel away from the work; hence, the stop acts positively to limit the infeed of the grinding wheel.

Ad just ment of feeding stroke The feeding motion of the cam is limited by the size and sha e of the cam. In order that the amount of feeding movement per cycle may be varied, I preferably make the upper arm of lever 130 as an involute shaped arm 145. By shifting the position of the slidable clamping member 142, which ,is secured to the end of the link chain, alon the arm 145, I change the effective length 0 the lever arm 145 and consequently vary the amount of feeding movement. The nearer the clamping mem er 142 is to the pivot point 131, the less the feeding movement. The greater the member 142 is from pivot 131, the reater the distance through which the mec anism will feed the wheel into the work. By making the lever 145 in the.shape of an involute of a circle, the*-clamp 142 may be adjusted along the lever without changing the relative position of the link chain and therefore without disturbing the position of the feed screw, since the chain merely wraps itself around the sprocket 138 and does not turn the screw when such adjustment is made.

In setting up the feed mechanism for any particular piece of work to be ground, the clutch 44 is thrown out of engagement and the work is mounted on the work supporting spindles. The locking screw 137 is then disconnected from the projection of the feed arm 94 so that the radially extending arm 135 swings downwardly into contact with the stop screw 146. The feed mechanism is now free so that the grinding wheel may be fed manually into the work.

The feed cam 110 is then rotated by manually turning the shaft 111 by lacing a wrench on the projection 134 unti the 01- lower roller 133 is a short distance from the abrupt rise in the cam. Thefeed mechanism 7 distance away the clamping is .then turned by means of the hand lever 92 until the grinding wheel reaches a position where the work has been reduced to its desired size. By withdrawing the micrometer adjusting plunger and turning the pinion relative to the feed gear, the feed arm 94 swings into substantial alignment with the arm 135 sothat the locking screw 137 may be screwed into place and lock the feed mechanism to the arm 135. It may be necessary at this point to adjust the micrometer device slightly to bring the arm 135 into'contact with the stop screw 146. It also may be necessary to make a slight adjustment of the stop screw 146 to be sure that the cam follower roller 133 does not touch the operative surface of the cam for a short distance before the abrupt rise is reached. If this adjustment is necessary, the operator will also have to make a further read ustment of the micrometer device to bring the work to the desired size.

In view of the above ex lanation, it will be understood that the fee screw is rotated in opposite directions through a definite distance and at a predetermined rate controlled by the contour shape and rate of movement of a cam, so that the grinding wheel moves cyclically and repeatedly through the same path of advance and retreat, or what may be termed an invariable cam cycle. The distance through which the wheel moves is therefore a function of the extent of a single rise and fall of the follower on the cam, and this may be varied by making ad'ustments of the stop and of the location 0 member 142 on the arm 145. These adjustments make it possible to regulate the rate of feed as we 1 as the distance of travel of the whee so that the rinding operation may be controlled as esired. It will also be understood that the adjustable stop makes it possible to grind with even greater precision of measurement than can be obtained by the use of the cam alone, since the stop may be set to sto the infeed of the wheel before the cam fo lower has reached the extent of its throw, i. e. the lowest point on the cam, and thereby prevent further infeed of the wheel and permit the grindin operation to die out gradually and so pro uce a fine finish on the work.

Work gripping and supporting mechanism and rotating device, to be effective, must engage the work close to the periphery thereof, so that the torque and the friction of the rotating members may be as high as possible, as compared with the retarding effect of the grinding wheel on the work. If the Work is gripped onl near its center line, there is a serious possi ility of slippage and consequent imperfect grinding. My device is so arran ed that it automatically centers the worIi, and it is not necessary to first provide the work with center punch markings or to make other provisions for this purpose. The particular type of work gripper used depends upon the shape of the work to be ground. In some cases, I employ members which engage only the endsof the work. If the work is hollow, I may utilize spring fingers fitting within the work to assist in supporting it.

In 111 preferred construction, shown in detail in Iigs. 3 and 4, I provide a simple arrangement for moving the work gripping members which is operated by a cam controlled weight-and linka e mechanism. As shown, the spindles 20 an 21 are axiallymovable and carry work gripping members at their inner ends which are forced into contact with the work and are rotated by the spindles. These spindlesiare moved axially by

levers

150 and 151 pivoted to the base at 152 and 153 respectively. The upper ends of these levers are each rovided with yoked portions 154 and 155 w ich are connected to move the spindles, which carry the work gripping members, axially towards and from the ends of the work. The lever 151 is shaped like a bell crank and has a downwardly extending portion 157 connected by the pivot pin 158 to the connecting rod 159. To move the two levers simultaneously inopposite directions, I provide the lower end of the lever 150 with a gear tooth projection 162, meshing with the teeth or pro ections 163 on the substantially T-shaped lever 164. The lower arm of the T-shaped lever 164 is connected by the pivot pin 165 to the connectin rod 159. The long arm 1680f the T-shape lever 164 supports through the rod 169 an adjustable weight 170. This mechanism, as clearly shown in Figs. 1, 3 and 4, is such that the weight normally acts to hold the work supporting members towards each other to grip the opposite ends of the work piece with an equalized. pressure.

To separate the work supporting s

indies

20 and 21 and thereby re ease the nished work and permit a new piece to be put into position for 'nding, I provide an adjustable, positive y actuated intermittent mechanism operating in timed relation with the wheel feeding mechanism. To this end, I provide a revoluble member arranged to strike the lower end of one of the spindle actuating levers and force it to move the grippers outwardly. As illustrated, I employ a roller 180 carried by the adjustable arm 181 rotatably mounted on the cam shaft 111. A projecting arm 182 is mounted in fixed position on the cam shaft 111 and provided at its outer end with an adjusting screw 183 and lock nut 184.

grinding Wheel slide. Depending from the pivot 158 on the bell crank 157 is an adjustable arm 187 carrying a pin or projection 188 so constructed and positioned that it is in the path of the roller 180. As the cam shaft 111 rotates, the adjusting screw 183 carries the roller arm 181 and the roller 180 about its axis. The roller 180 contacts with the pin or projection 188 and swings the linka e mechanism towards the left, thus moving the

arm

150 and 151 outwardly to separate the work gripping members on the supporting spindles. his construction provides means for yieldingly moving the spindles towards each other, so as to make the machine safe in its operation, and insures a positive separation of the spindles when the work has been finished.

Adjastmmits for work supports To vary the amount of movement of the work supporting spindles, I preferably mount the arm 187 so that it pivots about the pin 158. A projection 190 on the arm 187 is provided with an elongated slot 191 so arranged that the arm 187 may be locked in adjusted position to the lever 157 by a nut and screw 192 which passes through the slot 101. By swinging the arm 187 towards the right, one reduces the amount of motion transmitted to the work supporting spindles because the roller 180 will strike the in 188 only at the upper portion of the rol er and so contact therewith later and leave it sooner than would be the case if the pin 188 were lowered to be struck by the roller near a horizontal diameter. As shown in the drawings, the arm 187 is adjusted to the extreme left hand position to give a maximum relative movement to the work sup orting spindles.

To vary the distance supportmgs indles, I provide the

spindles

20 and 21 wit threaded

portions

200 and 201. Surrounding these threaded portions are a pair of double

race ball bearings

202 and 203 which engage the yoked

portions

154 and 155 of

levers

150 and 151 res ectively. To adust the positions of the ball bearings relative to the spindles, I provide a air of

nuts

204 and 205 so arranged that t e ball bearings may be moved a ong thethreaded portrons 200 and 201 and then locked in position. The ad ustment varies the distance between tween the work the work engaging members on the spindles to accommodate different lengths of work.

As a further means of varying the distance between the work supporting spindles to accommodate various lengths of work, I make the connecting rod or link 159 adjustable in length. This is preferably accomplished by means of a turnbuckle or other suitable arrangement. As shown, I may screw thread each end of the rod 159 and mount the threaded

couplings

206 and 207 thereon.-

Lock nuts

208 and 209 are provided respectively to lock the couplings in adjusted positions. After removing the pivot pin 165 from the pivotally mounted cou ling 206 and loosening the lock nut 208, t 1e operator may turn the coupling 206 relative to the rod 159 to shorten or lengthen the distance between

pivots

165 and 158 and thus vary the distance between the ends of the work supporting spindles. Likewise the other pivot pin 158 may be removed and the coupling 207 adjusted if a further adjustment is necessary.

To prevent a rapid dropping of the weight 170 and consequently a too sudden motion of the

spindles

20 and 21 in gripping a new piece of work, I preferably mount the weight 170 so that its lower portion acts as a dashpot piston (see Fig. 3). The piston or weight 170 is surrounded by a dash-pot cylinder 210 which is provided with an opening to the atmosphere controlled by an adjustable air valve 211 so arranged that the leakage of air may be regulated to cushion the motion of the weight. By varying the weight 170 and the adjustment air valve 211, the spindles may be moved slowly or rapidly towards each other and held in frictional contact with the ends of the work to be ground with sufficient pressure to support and rotate the work during the grinding o eration.

The bottom of the ash-pot cylinder 210 is provided with a series of openings or holes 212 to allow air to leak rapidly into the cylinder on the up stroke of t e piston or weight 170 and prevent retarding the releasing movement of the work supporting spindles. To prevent air escaping from the cylinder through the holes'212 during the downward motion of the piston, I place a soft, flexible disk 213 of leather, rubber or the like iii the bottom portion of the cylinder. The disk 213 acts as a valve and prevents the escape of air on the downward movement of the IS- ton. but permits air to readily raise the disk and enter the cylinder on the upward movement of the piston.

Wheel spindle reciprocating mechanical In grinding work of the class adapted for an automatic rinding machine, a wide faced wheel is emp oyed. A direct infeed of the wheel is used and the wheel is preferably of suflicient width to cover the length of the article being ground. To prevent uneven wearing of the grinding wheel face and to eliminate grain markings on the work, I preferably provide a relative oscillatin or reciprocating movement between the gr1nding wheel and the work. In my preferred construction, I have illustrated a reciprocating mechanism which moves the grinding wheel spindle axially by means of the rotative power of the wheel spindle. As shown in Fig. 1, the wheel spindle 18 is provided with a worm 215 attached to its outer end. The worm 215 meshes with a worm gear 216 mounted on the shaft 217 which also carries the eccentric or cam 218. On a parallel stud or shaft 219, I mount a yoked member 220 having a depending follower arm 221 adapted to contact with the operative face of the cam or eccentric 218. The upper end of the yoked member is provided with a pair of rollers which are adapted to ride in an annular groove 222 on the end of the worm 215 so that any motion of the eccentric or cam is transmitted through the ivotally mounted yoked member to move tiie grinding wheel spindle axially. A spring 223 engages th c yoked member 222 to hold the follower arm normally in operative contact with the eccentric or cam.

In grinding certain classes of work, such as work having a shoulder, it is sometimes essential that the grinding wheel be fed into the work without axial reciprocation of the wheel spindle. To this end, a manually operable lever 225 is pivoted to the housing of the oscillating its inner end with a projection having a cam face 226 which acts u on a corresponding cam projection 227 on t e yoked member 220 to hold the yoked member out of engagement with the surface of the eccentric 218 and prevent axial movemcnt of the grinding wheel spindle.

W ark feeding mechanism To make thegrinding machine fully automatic, I provide means for feeding the work automatically into grinding position on the machine. As illustrated in Figs. 5, 6 and 7, my preferred form of magazine feeding device comprises a turret wheel 230 having openings in its periphery to receive the pieces of work from t e hopper 231. The operator places the new pieces of work in the hopper 231 and they roll down the surface 232 and into pockets 233 formed in the two disks 234 whic make u the turret wheel 230. This Wheel is suita 1y mounted to rotate about an axle 235 carried on uprights 236 supported on the machine base. A projecting In 237 is mounted on the inside surfaces of eac upright 236 to prevent the new piece of work dropping into pocket 233 in the turret while grinding is going on, and at the same timekeeping two pieces from getting into the pocket at once. When the turret wheel mechanism and provided at rotates, the piece supported on the shelf formed by lugs 237 is forced into the adjacent pocket, and another piece of work rolls onto the shelf in the next pocket as it comes into position.

The turret wheel 230 may be rotated to present new pieces of work to the work supporting spindles by any desired means, but in my preferred construction, I utilize the influence of gravity to turn it and employ a cam operated mechanism to release the turret when the spindle gripping members have dropped the finished piece of work, and permit it to turn just enough to present the next piece to the work supports. To this end,

I provide the side of the turret wheel 230 with a ratchet wheel 240. A ratchet pawl 241 is slidably mounted in the boss 243 which is fixed to the upright 236. The ratchet pawl is held by spring pressure in engagement with the teeth of the ratchet wheel 240 to prevent rotation of the turret wheel in a direction to feed the work. To release the pawl 241 from the ratchet wheel 240 and permit the influence of gravity to act on the new pieces of work to turn the turret wheel, I preferably connect the ratchet pawl to the connecting rod 244 (Fig. 8), the other end of which is adjustably connected to the lever 245 pivotally mounted on the side of the base. The lower end of the lever 245 is provided with a cam face 246 adapted to be engaged by a second lever 247 pivoted to the base by a cap screw 248. The lever 247 is connected by means of a connecting link 249 to a projecting portion of the follower lever 132 so that motion of the cam follower 133 due to the abrupt rise portion of the cam is transmitted to raise the lever 247 and cause it to swing and contact with the cam portion 246 and thereby move the lever 245 to withdraw the pawl 241 from engagement with the ratchet wheel 240. This permitsthe force of gravity acting upon the new pieces of work in the turret wheel 230 to turn the wheel rapidly to bring the next piece of work into axial alignment with the work supporting spindle.

To keep the turret wheel 230 from'rotating too far and permit itto rotate just sufficiently to bring the next piece of work into axial alignment .with the work supporting spindles, I provide the ratchet wheel 240 with the same number of ratchet teeth as there are work openings in the turret wheel 230. A reduced portion of the ratchet pawl 241 within the projection 243 is surrounded by the spring 242 which exerts a sufficient pressure to hold the pawl in positionin contact with the ratchet wheel. The cam face 246 of the lever 245 is so shaped that the ratchet pawl may return rapidly into contact with the next ratchet tooth underthe influence of the spring 242 as soon as thelever 247 passes over the cam face 216. This movement is sufiiciently rapid so that the pawl catches in the notch next to the one from which it has just been released, and so stops the wheel when the next work piece is opposite the spindles.

In order that the lever 247 may ride downwardly over the cam face 246 without remov-.

ing the pawl from the ratchet wheel, I preferably make the lever 247 (see Figs. 8, 10 and 11) in two parts. As shown in Fig. 11, the outer swinging portion 251 is pivotally mounted to the lever 247 and is so shaped that on the upward movement, the lever 247 and portion 251 act as a single lever. On the downward movement, however, the portion 251 contacts with cam face 246 and swings upwardly so that it may pass by the cam face 246 without moving the ratchet pawl. \Vhen released from the supporting spindles, the piece of work that has been ground falls slightly into contact with its pocket and remains there to aid in turning the wheel to bring the successive pieces of work into their proper grinding positions. As shown in Fig. 5, the piece of work remains in the wheel until it is free to roll downwardly into a container 250 on the front base of the machine.

To position the pieces of work axially, I provide one of the uprights 236 with a spring 252 which projects so as to press against one end of the piece of work and force it to the right, as shownin Fig. 6, against the opposite upright or support 236 of the wheel 230 so that each piece of work is presented to the spindle in the same relative position. This spring 252 is preferably provided with an adjusting screw 254 threaded into the support 236 so that the tension of the spring may be adjusted.

Work supporting devices Of the various forms of work gripping and supporting devices which I may employ, I have illustrated two ty es (see Figs. 3, and 14) which are adapted ibr holding solid and hollow pieces respectively. In the form shown in Fig. 3, I utilize the cup centers 255 and 256 which are so shaped that they contact with the ends of the work 257 only adjacent the periphery of the work to centerand drive the same. The weight 170 and linkage mechanism which are connected to move the

work gripping members

255 and 256 axially are so adjusted that the weight holds these members against the work with sufficient ressure to rotate and center the work during the grinding operation.

The device shown in Fig. 14 is particularly useful where it is desired to grind the outer cylindrical surface of a work piece concentric with an internal cylindrical surface. In this case, the

spindles

20 and 21 are each provided with tapered

apertures

260 and 261 respectively to receive the correspondingly tapered

members

263 and 264. The outer ends of the

members

263 and 264 are provided with the reduced

portions

265 and 266 respectively which are adapted to center the work by its central opening. The

portions

265 and 266 are preferably constructed with spring fingers formed by cutting radially extending

slots

268 and 269 in the reduced end portions, these serving to center the work even though there are slight variations in the diameter of the holes or openings 270 in the work. The work is gripped between two

collars

272 and 273 which are slidably mounted on the spring finger ends 265 and 266. The outward movement of these collars is limited by the

shoulders

274 and 275 on the tapered

spindle members

263 and 264. The inner ends of the collars are adapted to frictionally engage the ends of the work with sufficient pressure to rotate the work during the grinding operation.

To permit the spindles to withdraw from the finished work, I employ

shedder members

276 and 277 mounted on the work supporting spindle housings on the front base of the machine. These shedder members extend downwardly and serve as yoke arms which engage the

annular grooves

278 and 279 in the

slidable members

272 and 273. When the

spindles

20 and 21 are withdrawn to release a finished piece of work, the

slidable members

272 and 273 are held against axial movement by the

yoke members

276 and 277. This permits the

portions

265 and 266 to slide within the

members

272 and 273 and withdraw from their supporting position in the o ening 270. As the

spindles

20 and 21 with raw, the shedder members hold the

slidable members

272 and 273 against endwise movement so that the

work supporting spindles

20 and 21 may withdraw from their gripping positions against the ends of the work. This permits the turret wheel to be rotated to bring the new piece of work into axial alignment with the work supporting spindles.

Power driven turret wheel It may be desirable in grinding some kinds of work to provide a turret wheel which is positively rotated to bring the new pieces of work successively into axial alignment with the work supporting spindles. To accomplish this, I may provide a mechanism which will operate intermittently to positively rotate the turret wheel to bring the work into grinding position. As shown in the drawings, such a construction comprises a turret wheel composed of the

disks

234 and 234 having pockets 233 to receive the pieces of work as they roll down the surface 232 of a hopper. The turret wheel is mounted for rotation on a shaft or stud 284 supported in the

uprights

236 and 236 mounted on the machine base. A. sprocket 287 is fixed on the wheel hub in the space between the

disks

234 and 234. A supporting bracket 288 is mounted on the machine base and has a shaft 289 journalled therein which carries a sprocket 290 on its outer end connected by a link chain 291 with the sprocket 287 to rotate the turret wheel.

To cause the shaft 289 to turn the turret wheel at aproper time, I may connect this shaft with the wheel feed mechanism so that the work will be fed in timed relation with the movement of the grinding wheel. To accomplish this, I mount a ratchet wheel 293 on the other end of the shaft 289 and provide a ratchet pawl 294 on the bracket 295 which swings about the axis of the shaft 289 to pick up the successive teeth of the ratchet wheel 293. To actuate the pawl, I provide a. connecting rod 299 which is connected to the lever 130 so that as the feed cam 110 turns the lever 130 is moved to revolve the turret wheel and bring successive pieces of work into grinding position. To prevent excessive rotation of the turret wheel which would carry the new piece of work past the grinding position, I may employ a friction device, which, as illustrated, comprises a friction collar or washer 296 held in frictional contact with the projection 297 of the turret wheel to retard the rotation thereof. I provide adj usting screws 298 which are screw threaded into the uprights 286 and bear against the outer face of the collar 296 to vary the frictional contact between the washer 296 and the projection 297. By tightening or loosening the screws 298 the friction between the collar and the turret wheel may be varied as desired.

A further modification of a turret wheel is shown in Figs. 17 and 18, in accordance with which I utilize the weight and force of the water stream, which is used to cool the work during the grinding operation, in order to aid in turning the wheel. The wheel is essentially the same as that shown in Figs.

. 5 and 6 and is operated by means of the cam controlled mechanism shown particularly in Fig. 8; but it is provided with pockets, and shaped somewhat like a water wheel, so that water may enter the pockets on the descending side nearest the grinding wheel and escape only when the pockets successively reach the bottom of their circular path of revolution. As illustrated, the work pieces 300 are supported on the

sides

234 and 234* of the wheel, recesses 303 being cut therein to form projecting lugs 304 which curve in such a manner as to hold the work in place. The peripheral portion 305 of the wheel which connects the sides is cut away to form spaced openings 306 and a set of curved walls 307 are formed, as shown in Fig. 17, in such a manner as to provide deep pockets to hold liquid. The

sides

234 and 234 form the ends of the pockets and prevent the escape of liquid therefrom until the work has assed below the grinding wheel 308 and is to e discharged. The ratchet 240 corresponds with the ratchet 240 shown in Figs. 5 and 8, and it is by means of this ratchet control mechanism that the rotative movement of the wheel The operation of the various mechanisms of the machine is apparent from the above description. In this machine, which is fully automatic in operation, the work is placed in the hopper 231 from which it rolls into successive pockets in the turret wheel 230. This wheel is rotated in timed relation with the other machine parts to carry the piece of work into substantial alignment with the

work supporting members

255 and 256. At this point, the

spindles

20 and 21 carrying the work supporting members are moved axially toward each other to grip the work and raise it slightly from the turret to support and rotate the work durin the grinding operation. This is accompligied by means of the weight 170 which moves at a rate determined by the valve adjustment of the dash-pot 210. The motion of the weight is transmitted simultaneously to the two spindles by the linkage mechanism shown in Fig. 3.

The cam controlling mechanism shown in Figs. 1, 2, 8 and 12 is constantly rotating, so that when the cam roller 133 has passed over the sharp rise in the cam 110, the cross feed screw 81 will then be rotated by the weight 143 in such a direction as to feed the grinding wheel into the work. This goes on until the arm 135 which rotates with the feed screw strikes the adjustable stop screw 146. For a shorttime thereafter, the roller 133 is held out of contact with the cam while the grinding wheel finish grinds the work. During this interval the cross feed mechanism is stationary.

Then the cam roller 133 starts up the steep rise of the cam 110 and moves the grinding wheel back ra idly against the pull of the weight 143. en the wheel is out of contact with the work, the roller 180 which is revolved b the cam shaft 111 then strikes the projecting member 188 on the spindle operating mechanism and thereby forces the spindles to separate and withdraw the work supporting members from engagement with c the ends of the work. The work then drops into its former position on the turret wheel, and a ratchet mechanism (see Fig. 8) operating in timed relation with the wheel cross feed mechanism is moved to release the turret wheel and permit it to revolve under the influence of gravity and bring the next piece of work into substantial alignment with the work supporting members, and the cycle of operations is then repeated.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A grinding machine comprising a work support and a grindin wheel and means for imparting a cycle 0 motion comprising a feeding and withdrawing of one toward and from the other including a cam which times and controls such feeding and with drawal and a follower engaging said cam and operating to cause a rotation between a screw and a nut by which the feeding movement is caused, or varied according to the varying radius of the cam.

2. A cylindrical grinding machine comprising a base, a rotatable grinding wheel and a worksupport thereon which are movable relatively towards and from each other, a cross feed screw and a nut contacting through a plurality of threads which are connected to cause such movement, and mechanism, including a movable cam of special contour and a follower, operatively connected to rotate the screw and nut relatively in opposite directions in a cycle timed by the cam and feed the wheel into the work through a predetermined distance and at a rate which is determined by the contour and the speed of said cam.

3. A grinding machine comprising a base, a rotatable grinding wheel and a work support thereon which are movable relatively towards and from each other, a cross feed screw and a nut contacting through a plurality of threads which are connected to cause such movement, a power operated cam mechanism, including a rotatable cam of special contour and a follower, operatively connected to turn the screw and nut relatively in opposite directions in a c cle timed by the cam and thereby feed the w eel throu h a predetermined distance into and away mm the work, the feeding movement being at a rate which is determined by the contour and speed of movement of the cam.

4. A grinding machine comprising a base, a rotatable grinding wheel and a work su port thereon which are movable relative y towards and from each other, a cross feed screw and a nut which are connected to cause said movement, a cam mechanism, including a cam of special contour and a follower, operatively connected to rotate the screw and nut relatively in opposite directions in a cycle timed by the cam and feed the wheel directly into and away from the work, and an adjustable stop arranged to limit the forward feed of the wheel into the work at a predetermined position irrespective of the movement of the cam.

5. A cylindrical grinding machine comprising a base, a work support thereon, a

grinding wheel mounted to move towards and relative to the work at a predetermined from the work, a cross feed screw and a nut point.

connected to move the wheel, power driven 10. A grinding machine comprising a cam mechanism, including a rotary cam and base, a grinding wheel slide 'mounted ther 5 a follower, connected to move the screw in on, a grinding wheel rotatably mounted on 7 a cycle timed by the cam and thereby feed the slide, means to support the work in rothe wheel into the work, and an adjustable tative and operative contact with the grind stop arranged to limit the forward feed of ing wheel, power operated mechanism, inthe grinding wheel into the -work at a predeeluding a. rotatable cam and a follower, to

10 termined position irrespective of the movefeed the wheel slide toward and from the 75 ment of the cam. work in a cycle timed by the cam, manuall 6. 4 rinding machine comprising a base, adjustable means to vary the length of fee a I'Otfil'llile grinding wheel and a work su ing stroke caused by t e cam and follower port thereon which are movable relative y acting through a full stroke, mechanism and towards and from each other. a cross feed a manually adjustable precision mechanism 30 such movement, mechanism. including a cam relative to the work. and a follower connected to rotate said feed 11. An automatic rinding machine comscrew and nut relatively in opposite direcprising a base, a sli e a rotatable grinding tions in a cycle timed by the cam and therewheel thereon, a work support to position as by move the screw through a predetcrthe work in rotative contact with the wheel, mined angular distance, and means associated a nut and screw mechanism to move the therewith for varying the angular distance slide and feed the wheel into the work, a through which said screw and nut are relapower driven mechanism, including a cam tively turned. g V and a, follower, to turn said screw in both an 7. A inding machine comprising a base, directions in a cycle timed by the cam, a

a rotatable grinding wheel and a work su micrometer device connected with said feed port thereon which are movable relative y screw to adjust the distance between the towards and from each other, a cross feed wheel and the work and an adjustable-stop o screw and a nut connected therewith to cause cooperating with said device to positively 0.1 such movement, mechanism including :1 0- limit the feeding movement of the wheel into tatable cam and connections between said the work irrespective of the cam movement. cam and the cross feed screw, arranged to 12. automatic grinding machine commove the screw in a cycle timed by the cam prising a base, a. inding wheel rotatabl to feed the wheel into the work, and means mounted thereon, means to support the work j for adjusting the length of feeding stroke of in rotative contact with the grinding wheel, the screw caused by said cam mechanism a cross feed screw and nut cooperating to without changing the position of the grindmove the grindin wheel and work relativeing wheel relative to he workly toward each ot er, a power driven mech- A cylindrical grinding machine anism, including a cam and a follower, to 105 p i g a base, a Work pp thereon, a oscillate said cmss feed screw and nut rela- 7 glmdlng wheel "l l F and from tively in a. cycle timed by the cam and a the work, mechanism, including a rotatable change speed mechanism in change th t cam and a follower, operatively connected f fe d of the grinding wheel into the Workto feed the wheel continuously into the work 13 A li d i l i di hi m- 110 and away therefrom in a cycle timed b the i i a base, a k support, a i di means to f the length of 6 of wheel movable towards and from the work, the wheel feeding movement caused by the 3 cm f d screw and a nut connected to cam and follower acting through a full move h wheel a power driven mechanism,

Stroke, and meanslllcluding an adjustable including a cam and a follower, effective to p to PP the Wheel at l' P 1 turn the screw and move the wheel in oppotion relative to the work before the cam folit di ti i c 1 ti d b th lower has reached the extent of its throw. d ll opera 1 means f feeding {I A cylindr l gr g machine P the wheel into the work beyond the point to prising a base, a r pp and g which it is moved by the cam mechanism. ing wheel movable relatively towards and 14, A yli d i l i di mgchihs comfrom each other, a cross feed screw and a i in ba a w k support thereon, a nut connected to cause such movement, mechi di h l bl t w rd and from w 15m, lnchldlng a cam and a follower, 6011- the wor mechanism, including a rotatable n nected to rotate the screw and nut relatively cm d a f ll connected t f d th .the wheel into the work and which is caused by said cam and follower acting through a full stroke.

, 15. A cylindrical grinding prising a work support, a rindin wheel mounted to move towards an from t e work and parallel with its own axis, across feed screw and aunt connected to move the wheel, mechanism, including a cam and a follower operatively connects to turn the screw an nut relatively-1n opposite directions in a cycle timed by the cam and thereby move the w eel towards and from the work, and means operating automatioall to reciprocate the wheel axiall througlra s ort distance during the grinding operation.

16. A ding machine comprising a base, a slide ereon, a grinding vw eel rotatably mounted on the slide, means to support the work in operative relation with the grinding wheel, a cross feed screw 0 ratively connected to move the slide in 0th directions, means for yieldably turning the screw to fee machine comdevice to re ate the rate of rotation of the screw and to move the grinding wheel away from the work.

17. A 'nding machine comprising a base, a cross s 'de on said base, a grinding wheel thereon, meansto sup rt the work in operative relation with ,t e wheel, a rotatable feed screw connected with the slide, a weight connected to rotate said screw and feed the wheel into the work, a positively rotated cam a d to control the movement of the slide town the work and to move it positively in the opposite direction.

18. A c lindrical grindin machine comprising a ase, a grin g w eel-and a work so port thereon which are movable towards and from each other, a cross feed screw and a nut operatively connected to cause such movement, means for yieldingly turning the. screw to feed the wheel into the work and l1power driven mechanism, including a cam an a follower, connected to regulate the rate of rotation of the screw in one direction and to move it positively in the o' posite direction, and thereby cause the whee to be fed into the work and removed therefrom in an invari able caAn clhe. 1 b v 19. grin 'ng machine com rising a ass a work support thereon, a gi'inding wheel mounted to move relative to t e work, a cross feed screw and a nut connected to move the wheel, a rotatable cam, a cam follower therefor, and means includm alever o eratively connected between the to ower an the cross feed screw to rotate the latter in opposite directions in a cycle timed by said 20. A grinding machine comprising a base a work support thereon, a tgrinding whee mounted to move relative to e work, a cross feed screw and a nut connected to move the wheel, a rotatable cam, a cam follower thereas for, means including a lever operativelycona cam control the work without changing the speed of the cam.

21. A grinding machine comprising a base, a slide thereon, a rotatable grinding wheel on the slide, a cross feed screw connected to move the slide in both directions, a power driven cam, a cam follower mounted on an arcuate lever and a chain and sprocket connection between the lever and the screw, which are so arranged that the efi'ective length of the lever arm may be varied to chan the length of wheel feeding stroke without 0 an ing the relative positions of wheel and wor 22. A grinding machine comprising a base,

work supporting and rotating members whic are relatively movable to 'p a piece of work, a grinding wheel mounted to move towards and from the work, a cross feed screw and nut connected to cause the wheel movement, mechanism, includin a cam and a follower operativeliy connects to rotate the cross fee screw an nut relatively in opposite directions in a cycle timed by the cam, and means to cause the work supporting members to ri and release the work in timed relation wit the wheel movement.

23. A. grinding machine comprising a base, work supporting and rotating members which are relatively movable to grip a piece of work, a grinding wheel mounted to move towards and from the work, a cross feed screw and nut connected to move the wheel, means, including a cam and a follower, operatively connected to oscillate the screw in opposite directions in a cycle timed by the cam, mech anism operating in timed relation with the s members and means to adjust the time o operation of said mechanism relative to the cam movement.

work supporting and rotating members thereon which. are relatively movable to grip a piece of work, mechanism movable to present pieces of work successivel "to said members a grindin wheel movable relative to the wor to grind t e same a crossfeed screw connected to feed the wheel into the work, mechanism, including a cam and a follower, operatively connected to move the screw in a do timed by the-cam and thereby feed thew eel towards and from the work and mechanism operating in timed relation with the cam movement toactuate the work presenting mechanism and to move the work grippin members relatively when the wheel is out 0 contact with the work.

. 25, 'A machine comprising a base, work supporting and rotating members theregrinding machine comprising a base,

on which are relatively movable to grip a piece of work, mechanism movable to present pieces of work successively to said members, a grinding wheel movable relative to the work to grind the same, a cross feed screw and a nut operatively connected to move the wheel, mechanism, including a cam and a follower, operatively connected to oscillate the screw in opposite directions in a. cj'cle timed by the cam and'mechanism operating in timed relation with the cam movement to actuate the work presenting mechanism and to move the work gripping members relatively when the wheel is out of contact with the work.

Signed at Worcester, Massachusetts, this 15 24th day of Sept.,1925. 7

CHARLES H. NORTON.

on which are relatively movable to grip a piece of work. mechanism movable to present pieces of war successively to said members, a grinding wheel movable relative to the work to grind the same, a cross feed screw and a nut operatively connected to move the wheel, mechanism, including a cam and a follower, operatively connected to oscillate the screw in opposite directions in a cycle timed by the cam andmechanism operating in timed relation with the cam movement to actuate the work presenting mechanism and to move the work grippin members relatively when the wheel is out 0 contact with the work.

24th day of Sept, 1925.

CHARLES H. NORTON.

CERTIFICATE OF CORRECTION.

Patent No. 1,779,823. Granted October 28, 1930, to

CHARLES H. NORTON.

It is hereby certified that error a ears in the abov requiring correction as follows: Page 11, l ine 18, claim 6, if izi l ldis insert a comma; same page, line 79, claim 10, strike out the word "mechanism'" page 12, line 91, claim 22, after the word "including" strike out the comma In the drawings, at the bottom of sheet 1, insert "Witnesses Chas 25:32:20 :laroldrW. Eaton"; glad that the said Letters Patent should be read orrec IOIIS erein use in the Patent officet at the same may conform to the record of the Signed and sealed this 9th day of December, A. D. 1930.

I M. J. Moore, Acting Commissioner of Patents.

(Seal) CERTIFICATE OF CORRECTION.

Patent No. 1,779,823. Granted October 28, 1930, to

CHARLES H. NORTON.

It is hereby certified that error appears in the above numbered patent requiring correction as follows: Page 11, line 18, claim 6, after "follower" insert a comma; same page, line 79, claim 10, strike out the word "mechanism"; page 12, line 91, claim 22, after the word "including" strike out the comma.

In the drawings, at the bottom of sheet 1, insert "Witnesses Chas. H. Richards. Harold W. Eaton."; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 9th day of December, A. D. 1930.

M. J. Moore,

(Sell) Acting Commissioner of Patents.